1. Field of the Invention
This invention relates to an apparatus for working flat stock, and is directed more particularly to apparatus adapted to "read" the configuration of a pattern on, for example, a piece of paper, and trace the identical configuration in a piece of flat stock at a station remote from the pattern, for the purpose of cutting or otherwise removing material from the flat stock, or for the purpose of adding matter to the flat stock, such as adhesive, or for the purpose of welding, or the like.
2. Description of the Prior Art
It is known to provide a coordinate drive tracer, a device which traces the edge of a line or a silhouette template, to guide flat stock working equipment to produce a duplicate of the template in wood, steel, stone, or glass. The tracer includes two lamps, mounted at the bottom of the unit, which project a well defined light spot on the pattern. The light is reflected from the pattern to a photocell in the tracer unit. The photocell signal is processed by a photocell board and a logic board to produce sine and cosine signals for X and Y axes, respectively. The unit communicates with X and Y drive motors to cause the unit to be moved along the pattern. Pattern changes in direction are sensed by the photocell which initiates command signals that provide proper changes in speeds for each drive motor. A unit of this type is shown and described in U.S. Pat. No. 4,160,199, issued Jul. 3, 1979, in the name of Francis G. Bardwell.
While the line tracer itself is known, typically such tracers are sold independently of the apparatus needed to make use of the units. Accordingly, a wide range of carriage configurations for mounting tracer units and tool holders for mounting a wide range of working tools have emerged, usually with less than wholly satisfactory performance. Because the apparatus, in use, is constantly in transition, stability of the unit is of utmost importance. Slight deviations between the movements of the tracer unit and the tool holder result in imperfect duplications of the pattern. To insure stability, many users have constructed very heavy carriage assemblies and support assemblies, adapted to insure stability. Unfortunately, use of many solid steel components, while ensuring stability, has escalated costs of building and shipping the machines, and also escalated costs of running the machines which requires relatively high-powered drive motors to move the rather massive carriage components.
Accordingly, there is a need for a complete apparatus including a line tracer units a carriage assembly, and a tool holder unit, all arranged so as to facilitate readiness for operations upon receipt, to cost substantially less to fabricate and ship and operate, and yet provide stability and accuracy in repeated operations.